Sjögren's syndrome is an autoimmune disorder involving exocrine glands that occurs alone or in association with various autoimmune and connective tissue diseases. The severity of Sjögren's syndrome ranges from isolated sicca syndrome to severe complications such as vasculitis, lung and renal involvement. Overt or latent renal tubular acidosis caused by autoimmune tubulointerstitial nephritis, is a common extraglandular manifestation in Sjögren's syndrome. Osteomalacia is a rare complication of renal tubular acidosis, and it was reported to be associated with distal renal tubular acidosis in Sjögren's syndrome. We report a 60-year-old woman who presented with multiple bone deformity and general muscle weakness. Osteomalacia was secondary to Fanconi's syndrome, and the Fanconi's syndrome was a result of renal involvement in Sjögren's syndrome. Fanconi's syndrome is a rare kidney manifestation in Sjögren's syndrome. It may be latent and may precede the subjective sicca symptoms. These findings suggest that evidence for Sjögren's syndrome should be sought in adult patients with unexplained osteomalacia and renal tubular acidosis, even in the absence of subjective sicca syndrome. Conversely, in patients with Sjögren's syndrome, early investigation and treatment of renal tubular dysfunction may prevent future complications, such as osteomalacia.